Wow... that's really a tough question. I can say, "I'm not this
  mug of coffee next to me" yet I'm drinking from it, so its
  contents become a part of me quite literally and so, the coffee
  becomes me (part of), so I can say the coffee is/will be me in a
  sense. Also, when I pick up the mug, my brain incorporates the
  mug into my body, considering it as part of me. [Heidegger was
  correct 80 years ago: the tool really DOES become you]. So, I
  can say the mug of coffee next to me *is* me in a sense: I can't
  say it's NEVER me because sometimes it is. Tougher question than
  I would've expected.